MyCar = 0

usermessage.Hook("YourCar", function(msg)
	MyCar = msg:ReadShort()
end)

timer.Create("SetSolid", 1, 0, function()
	for k,v in ipairs(ents.FindByClass("prop_vehicle_jeep")) do
		if v:EntIndex() == MyCar then
			v:SetNotSolid(false)
		else
			v:SetNotSolid(true)
		end
	end
end)